Infrared spectra of the crystalline inorganic borates

Abstract

Infrared absorption spectra of anhydrous, crystalline, inorganic borates were obtained in the 2000 cm-1 to 300 cm-1 range. Compounds with B10 and B11 isotopes were prepared to assist interpretation. Spectral bands for all orthoborates and pyroborates and some metaborates could be assigned satisfactorily. Borates with complex ring-type anions generally exhibited spectra of such complexity that only superficial interpretation was attempted. From correlations between spectra and structure it appears that boron in 3-fold or in 4-fold coordination can be identified with reasonable assurance on the basis of the infrared spectrum alone. Absorption bands are tabulated for about 80 borates and typical spectra are shown.